The manufacture of absorbent articles such as diapers, training pants, incontinence underwear articles, and the like, typically includes compiling and processing a web substrate as a continuous band of end-to-end or side-to-side work pieces from which respective absorbent articles are eventually derived, typically one absorbent article from each work piece. The compiling and processing includes assembling various elements to the web substrate, and shaping and configuring the thus assembled composite web substrate.
Upon completion of the various manufacturing steps, the web is severed across a transverse dimension of the web, typically across the full width of the web, to thereby separate from the web respective ones of the work pieces as separate and distinct units of absorbent article product.
During the fabrication process, the units of product become progressively defined in the work pieces until such time as the work pieces are severed from the web as separate and distinct units of product. In the web, the work pieces are generally associated with respective repeat elements on the web and the number and positioning of the respective elements in the finished units of product.
Thus, one familiar with the definition of the products to be derived from the web can, by observing the locations and repeat frequencies of respective elements on or in the web, typically perceive the identities and locations of respective ones of the work pieces on the web, and can correspondingly perceive the identities and locations of the respective units of product which will be derived from the web.
In manufacturing certain absorbent articles, trim material pieces are defined in trim areas; and the trim material pieces are severed and removed from the web. Exemplary of such trim areas are cut-outs associated with leg openings such as in, for example, diapers, training pants, incontinence underwear articles, and the like.
Successfully severing the trim material pieces from the web at the trim areas requires that the composite web material be severed about the entirety of the boundary between the trim material and the balance of the web.
Removing apparatus is typically designed for removing a trim piece that has been completely severed, and is typically not designed for completing severance where the trim piece has been only partially severed. Accordingly, successful removal of the trim pieces from the web at the trim areas is generally limited to work pieces where the corresponding web material has been completely severed from the web by the time the respective thus cut-out area, and associated trim piece, arrive at the removing station on the fabrication line.
Thus, successfully removing the trim piece depends heavily on the success of the severing step in severing the trim piece about the entirety of the boundary of the trim area with the web. When the trim piece is not completely severed, there is a high probability that the removing apparatus will not successfully remove the trim piece from the web.
Cutting apparatus typically employed in making leg cut-outs in disposable absorbent diapers periodically fails to completely sever the trim piece from the web. When that happens, the trim piece typically stays with the web, and when the respective work piece is cut from the web, the trim piece stays with the resulting unit of product, as a product defect.
It is an object of the invention to provide a method of checking for or verifying successful removal of trim material from trim areas at periodic intervals along a web in a processing line fabricating discrete units of product.
It is another object to provide such a method utilizing marking material on trim material pieces, removing the trim pieces which contain the marking material, and then sensing for the marking material to detect trim pieces not successfully removed.
It is still another object to provide such method wherein the marking material on the trim pieces is distinguishable from any indicator material used on the web outside the trim areas.
Yet another object is to apply a sensor for the marking material in sufficient proximity to the web and at suitable orientation to the web, thereby checking for trim material not successfully removed.
Still another object is to provide a web including marking material, confined in the trim areas, and which can be detected by a sensor, whether by visible light, or independently of visible light utilizing, for example, magnetic flux, ultraviolet light, an olfactory sensor, infrared energy, and/or an optical brightener detectable under ultraviolet light.
A more specific object is to provide such web free from the marking material outside the trim areas, such that the sensor can distinguish marking material, on trim material not successfully removed from the web, from other indicator material which may be present on the web.
Yet another object is to provide a method wherein a sensor is effective to sense the marking material through a visually obstructive layer between the sensor and the reference marks.
A further object is to provide apparatus for checking for successful removal of trim material from a web, including a sensor in sufficient proximity to the web, and at suitable orientation to the web, to be activated by marking material which is on the trim material and which comes into sensing proximity to the sensor, thus to check for successful removal of the trim material.
A more specific object is to provide for registering the marking material to a master reference on the respective work piece.
Yet another object is to provide the marking material as marks consistent with sufficient acuity and measurable intensity, and having suitable outline, that images thereof can serve as registration marks against which other elements in the web can be registered.
A yet further specific object is to provide for registering to each other, optionally indirectly, first and second web features, at least one of which is not sufficiently sharply or distinctively defined to be readily located by a sensor.
A more specific object is to provide methods, webs, and apparatus, directed toward reliably determining whether trim material has been successfully removed from leg cut-out trim areas in absorbent personal care articles such as diapers, training pants, incontinence underwear articles, and the like.
A first family of embodiments of the invention comprehends a method of checking for successful removal of trim material from trim areas disposed at periodic intervals along a web in a processing line fabricating discrete units of product from the web, thus to develop cut-outs in the units of product at the trim areas. The method comprises utilizing marking material as images, optionally as reference marks, on trim material pieces, and severing and removing the trim material pieces thus to develop the cut-outs at the trim areas, and after removing the trim material pieces, sensing for the marking material which was on the removed trim material pieces, utilizing at least one sensor at least at and adjacent the trim areas. The method thus detects marking material on trim material pieces which have not been successfully removed from the web. The marking material as perceived by the sensor or sensors is distinguishable from any indicator material used on the web outside the trim areas.
In preferred embodiments, the web, outside the trim areas, is free from the specific marking material used for the registration and/or reference marks, thus enhancing the sensor""s capacity to distinguish marking material not successfully removed from the web, from other markings or indicator material or indicia which may exist on the web.
Preferably, the marking material as applied in the trim areas is consistent with sufficient acuity and measurable intensity, and has suitable outline, that images thereof can serve as registration reference marks.
In some embodiments, the marking material as applied is consistent with sufficient acuity and measurable intensity, and has suitable outline, that the images thereof can readily be detected as registration reference marks by suitable such sensors having relatively low sensitivity and relatively low resolution capabilities, whereby low cost sensors can be successfully used in implementing the invention.
In preferred embodiments, the marking material as utilized at the trim areas is detectable using a suitable such sensor independently of visible light emanating from, or reflected from, a respective one of the reference marks. The marking material can be detected, for example and without limitation, utilizing magnetic flux, energy in the ultraviolet spectrum, an olfactory sensor, energy in the infrared spectrum, and/or an optical brightener detectable through action of energy in the ultraviolet spectrum.
Where the reference marks are to be detected using magnetic properties, the method can include creating the reference marks using magnetic ink, passing the reference marks through a magnetic field to magnetize the reference marks, and moving the magnetized reference marks past a sensor responsive to magnetic flux thus to sense the reference marks.
Methods of the invention can include generating heat selectively in the reference marks and detecting the heat using an infrared sensor, using fragrance detectable by an olfactory sensor to create the reference marks, using a dark ink sufficiently dark that the ratio of opacity of the reference mark to opacity of the web around the reference mark is no more than about 0.67/1, and including detecting or sensing for the reference mark at the trim area utilizing an optical sensor.
The composition of the marking material used in making the reference marks can include, for example, magnetic ink detectable by passing the ink through a magnetic field, fragrance detectable by an olfactory sensor, a material detectable by a sensor sensitive to energy in the ultraviolet spectrum, a material which can be activated to emit energy in the infrared spectrum, and/or an optical brightener detectable through action of energy in the ultraviolet spectrum.
Methods of the invention can further include sensing for the reference marks off-line, independently of visible light from the reference marks, after fabrication of the units of product has been substantially or fully completed.
The method further contemplates the combination of the reference marks, at least one sensor, and a controller operating in control of the fabrication line, having capacity to discern up to about 1000 of the reference marks per minute along a length of the web.
The method also contemplates distinguishing the reference marks from other material on the web on the basis of a difference between a first color of a respective reference mark and a second color of web material adjacent the reference mark.
The methods yet further contemplate culling units of product associated with trim areas wherein the at least one sensor detects a trim area reference mark downstream of the operation at which the trim material was to have been removed.
Some embodiments include utilizing at least two separate and distinct ones of the reference marks in given ones of the trim areas.
In preferred embodiments, the method contemplates removing the entirety of the marking material from the web at the severing and removing step, and after sensing for a respective reference mark at a respective cut-out, severing the web adjacent the respective cut-out and thereby creating a respective one of the discrete units of product containing the respective cut-out.
In preferred embodiments, the reference marks have leading edges sufficiently sharply-defined as to be readily discerned by suitable such sensors having relatively low sensitivity and relatively low resolution capabilities, with sufficient resolution that the reference marks can serve as reference loci to which other web elements can be registered. In such embodiments, the method further comprises applying the reference marks and a first set of web features periodically along the length of the web, using a common application device to force registration of the first set of web features to the registration reference marks.
The methods further contemplate (i) sensing timing of a respective reference mark coming into sensing proximity to a fixedly mounted such sensor, (ii) based on the timing of the reference mark coming into sensing proximity to the sensor, defining the location of a respective trim area associated with the respective reference mark, (iii) removing the trim material associated with the respective trim area according to the location of the trim area so defined, and (iv) subsequently sensing for the marking material at and adjacent the trim area to establish that the marking material has in fact been removed, and thus to establish that the respective trim material piece has been removed.
Methods of the invention can further include, after employing severing and removing apparatus to sever and remove the trim material, and after sensing for removal of the trim material, passing the trim area through the sensing zone of a metal detector or a magnetic field detector as a back-up sensor for detecting any reference mark marking material not successfully removed from the web.
In preferred embodiments, the methods contemplate utilizing a suitable sensor or sensors, in combination with a suitable composition and/or structure of marking material so as to be able to sense for the marking material through a visually obstructive layer which may be disposed between the sensor and marking material on any trim areas still on the web at the respective locations on the processing line. For example, where a trim material piece is only partially cut away from the web, and wherein an element of the trim piece is still attached to the web, however insecurely, the partially cut away piece will likely fold over as it passes along the length of the fabricating line. With the trim piece folded over, the underlying web structure/substrate, on which the marking material is applied, is positioned between the sensor and the marking material.
In preferred embodiments, the units of product comprise absorbent personal care articles, each such absorbent personal care article having ones of the cut-outs, derived from opposing sides of the web, on opposing sides of the respective personal care article.
In a second family of embodiments, the invention comprehends a method of checking for successful removal of trim material from trim areas disposed at periodic intervals along a web in a processing line fabricating discrete units of product from the web. The method comprises defining the trim areas; applying to trim material in successive ones of the trim areas, marking material as reference marks which can be detected by a sensor; removing the trim material from the respective trim areas, including removing the reference marks; and after removing the trim material, applying the sensor, in sufficient proximity to the web and at suitable orientation to the web, to the trim area to sense and detect presence of trim material not successfully removed from the respective trim area by sensing for marking material at and adjacent the respective trim areas, and thereby checking for trim material pieces not successfully removed from respective trim areas.
In a third family of embodiments, the invention comprehends a web used in fabricating discrete units of product. The web comprises trim areas, corresponding trim material in the trim areas, and marking material which can be detected by a sensor independently of visible light from the marking material, the marking material being confined in the trim areas. The web is free from the marking material outside the trim areas such that the sensor can distinguish marking material, on trim material not successfully removed from the web during a trim removal step, from other indicator material which may be present on the web.
In some embodiments, the marking material as applied being consistent with sufficient acuity and measurable intensity of reference marks, and having suitable outline, to serve as reference loci to which other web elements can be registered, and preferably to be readily so detected by a sensor having relatively low sensitivity and relatively low resolution capabilities.
Preferably, the marking material as utilized at the trim areas is detectable by action of magnetic flux such as by moving the marking material past a magnetic sensor, or by action of energy in the ultraviolet spectrum, or by action of an olfactory sensor, or by action of energy in the infrared spectrum, or through action of energy in the ultraviolet spectrum.
The marking material thus preferably comprises magnetic ink which can be detected by bringing the ink into sensing proximity with a magnetic sensor, or an optic brightener detectable by action of ultraviolet energy, or fragrance detectable by an olfactory sensor, or ink susceptible to emitting a readily detectable level of infrared energy.
In preferred embodiments, the marking material as applied to the web has sufficient acuity and measurable intensity to serve as reference images, and has suitable outline, for example leading edges sufficiently sharply-defined, as to be readily discerned by a sensor having relatively low sensitivity and relatively low resolution capabilities, with sufficient resolution that the reference images can serve as reference loci to which other web elements can be registered, and such that a suitable such sensor can preferably discern up to about 1000 of the reference images per minute along the length of the web.
In some embodiments, the web comprises at least two separate and distinct reference images each in given ones of the trim areas.
Preferred such webs of the invention comprise predominantly elements compatible with fabricating personal care absorbent articles from the web.
A fourth family of embodiments comprehends quality assurance manufacturing apparatus for checking for successful removal of trim material from areas disposed at periodic intervals along a length of a web. The apparatus comprises control apparatus including a timing system, defining the trim areas, and thereby defining the trim material to be removed from the web; marking apparatus applying, to the trim material in successive trim areas, marking material as reference marks which can be detected by a sensor; removal apparatus removing the trim material from respective trim areas, including removing the reference marks; and a sensor in sufficient proximity to the web, and at suitable orientation to the web, to be activated by the marking material applied to the trim material and coming into sensing proximity to the sensor, thus to check for successful removal of respective units of the trim material.
In some embodiments, the marking material has magnetic properties, active by the time the trim material is removed. The sensor is activated by the magnetic properties, and the quality assurance apparatus further comprises a metal detector downstream of the sensor, and operating as a secondary detector detecting magnetic properties of any marking material still on the web, or on units of product made from the web, by the time the web or respective units of product arrive at the metal detector.
The sensor is preferably adapted and configured to sense the reference marks independently of visible light from the reference marks, for example by action of magnetic flux, or by action of energy in the ultraviolet spectrum, or by action of an olfactory sensor, or by action of energy in the infrared spectrum, or through action of energy in the ultraviolet spectrum.
The apparatus can comprise a heater adapted, configured, and positioned to heat the reference marks on the fabrication line, and an infrared sensor detecting heat emanating from the so-heated reference marks.
In some embodiments, the sensor is adapted and configured to sense reference images having ratios of opacity of the image to opacity of the web around the image of no more than about 0.67/1, in which instance the sensor may be a low sensitivity and low resolution sensor.
In typical embodiments, the marking apparatus deposits on the web reference marks which, as applied, are consistent with sufficient acuity and measurable intensity of reference mark, and suitable outline, that the sensor and the control apparatus can, in combination, discern up to about 1000 of the reference marks per minute along the length of the web.
The quality assurance apparatus preferably includes a cull unit responsive to the sensor, preferably through the control apparatus, culling units of product sensed as having marking material thereon after moving past the removal apparatus.
Especially in embodiments utilizing marking material comprising significant quantities of metallic material therein, the quality assurance preferably includes a metal detector downstream of the sensor, as a back-up second sensor detecting any marking material not successfully removed from the web along with the trim material at the removing step.
In preferred embodiments, the sensor is effective to sense the marking material through a visually obstructive layer between the sensor and the reference marks.